Symmetry: Notice that $W_N^{k+N/2} = -W_N^k$. Is property ka use karke calculations reduce hoti hain.
For $k = 0, \dots, N/2-1$:

FFT calculations ko visualize karne ke liye "Butterfly Diagram" use kiya jata hai. Yeh dikhata hai kaise inputs combine hokar outputs bante hain.

Steps for N=4 DIT FFT:

Bit Reversal: Input samples ko bit-reversed order mein arrange karo.
Original Index (Binary) -> Bit-Reversed Index (Binary)
00 ($x_0$) -> 00 ($x_0$)
01 ($x_1$) -> 10 ($x_2$)
10 ($x_2$) -> 01 ($x_1$)
11 ($x_3$) -> 11 ($x_3$)
So, input order becomes: $x_0, x_2, x_1, x_3$.
Stages: $N$ samples ke liye $\log_2 N$ stages honge. N=4 ke liye $\log_2 4 = 2$ stages.